For example suppose I wish to replicate the simple command
echo testing > temp.txt
This is what I have tried
var util = require('util'),
spawn = require('child_process').spawn;
var cat = spawn('echo', ['> temp.txt']);
cat.stdin.write("testing");
cat.stdin.end();
Unfortunately no success
You cannot pass in the redirection character (>) as an argument to spawn, since it's not a valid argument to the command. You can either use exec
instead of spawn, which executes whatever command string you give it in a separate shell, or take this approach:
var cat = spawn('echo', ['testing']);
cat.stdout.on('data', function(data) {
fs.writeFile('temp.txt', data, function (err) {
if (err) throw err;
});
});
You can either pipe node console output a la "node foo.js > output.txt" or you can use the fs package to do file writing
echo
doesn't seem to block for stdin:
~$ echo "hello" | echo
~$
^ no output there...
So what you could try is this:
var cat = spawn('tee', ['temp.txt']);
cat.stdin.write("testing");
cat.stdin.end();
I don't know if that would be useful to you though.
exec
.const { exec } = require( "child_process" );
exec( "echo > temp.txt" );
Not sure what the pros/cons are between exec
and spawn
, but it does allow you to easily run the full command and write it or append it to a file.
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